Drowning in Noise

Southern resident killer whales are in serious trouble. Their population totals 78, positioning them on a countdown to extinction. In our previous blog, we talked about how the lack of salmon is a threat to orca recovery. Another major threat to their survival and growth is noise in the waters of the Salish Sea.

Sounds are produced by squeezing air between balloon-like sacs in their heads. Illustration by Uko Gorter

The sources of this noise are varied: oil tankers and freighters, ferries, cruise ships, commercial and private vessels, naval sonar, underwater construction, drilling, and resource exploration. The combination and growth of these sources mean that noise pollution in our waters is on the rise.

Here in BC, the number of oil tankers transiting through critical orca habitat would increase to 34 each month—up from five right now—with the expansion of the Kinder Morgan pipeline. That would dramatically increase noise resulting from propellers in the Salish Sea to the detriment of the fragile orca population. And that is just one of many projects being considered in the region which would result in more ships and more noise beneath the sea.

Hearing is essential for orcas. They use it to hunt for food, navigate their environment, and communicate with one another. Orcas produce sound by forcing air through the nasal passages in their head. They then focus and project these sounds through their melon, a fat-filled area in their forehead. When the sound waves hit an object, whether that be a fish, a rock or a boat, they bounce back and are received through a fat-filled cavity in the lower jawbone. From there, the sound then travels to the inner ear and into the brain where an image is formed. This is called echolocation.

Whales send out a rapid series of short clicks, using a fatty part of its head (called the melon) to focus the clicks in one direction. The clicks hit an object and bounce back to the whale’s throat and jaw and then up to the ear. Illustration by Uko Gorter

Orcas rely on an echolocation sensory system that is the most advanced on Earth—it gives them the ability to ‘see’ what’s in front of them. The ability to ‘see’ using sound waves is not something we can comprehend. Scientists, however, believe the sounds that orcas use to communicate go beyond hunting and navigation. They think it helps tie families together and calms individual orcas who can hear and communicate with their family, making them feel safe and connected.

The impacts on orcas of the current and growing noise levels in their critical habitat needs to be better understood. Current noise levels along the West Coast, where orcas live, need to be measured and capped over the longer term, reducing them to levels that do not harm the orcas.

How you can help

To truly protect and recover the southern resident orca community, we need to address the major threats immediately. That requires hard work and commitment from all sectors and levels of government, and even you! Together, we can give orcas a voice and a path to protect their pods and rebuild their numbers.

Change needs to start now so we can successfully turn the tides for this unique and important family. Orcas can’t wait—the time to act is now!

Thank you for reading our blog and submitting a comment. In regards to your question, many factors contribute to how harmful different sources of noise are. Scientists have found that baleen whales, such as humpbacks or gray whales, are more affected by low-frequency noises as they fall within their hearing range. Large commercial ships tend to emit low-frequency sound. Toothed whales such as orca or beluga whales are more sensitive to medium and high frequency sounds, which are often produced by smaller vessels like pleasure craft boats. Sound emitted by any vessel is affected by many factors such as the type of engines, the type of propellers, the speed of the vessel, the distance of the vessel from wildlife, and even the temperature and salinity of the water. I have added a link for you that will provide more information on studies that have been conducted and what scientists have found in regards to noise pollution in the Salish Sea and the effects on whales. I hope this information answers your question.http://www.smruconsulting.com/different-ships-produce-different-amounts-of-noise/

Please Help the Orcas and reduce the sound now that is hurting and killing them. Spread the word, and lets make this a success through common sense, science and better regulation. We must not allow Orcas of the Salish Sea to become one more extinction under our watch.

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I support Georgia Strait Alliance because the work they do is making a difference; it’s making it better for everybody. Together, we are protecting this incredible place that continues to fascinate me.